Method of biological purification of liquids.



' No. soms?. PATENTBD DB0.19,1905

W. P. DUNBAR.

METHOD 0F BIGLOGIGAL PRIFIGATION OF LIQUIDS.

APPLICATION FILED JUNE 9.1904.

La. AJ*

No. 807,667. PATENTED DEO. 19, 1905. W. P. DUNBAR. METHOD OF BIOLOGICALPURIPICATION OF LIQUIDS.

APPLICATION FILED JUNE 9, 1904.

3 SHEETS-SHEET 2.

No. 807,667. PATENTED DEC. 19, 1905.

vW. P. DUNBAR.

METHOD OP BIOLOGICAL PURIFIOATION OP LQUIDS.

APPLICATION FILED JUNBQ. 1904. i

a sHBETsnsHELT a4 UNITED STATES METHOD OF BIOLOGICAL PURIFICATHON OFLIQUIDS..

Specification of Letters Patent.

Patented Dec. 19, 1905.

Application filed June 9, 1904. Serial No. 211,784.

T0 (all whom, it muy concern:

Be it known that I, WILLIAn PHILIPPs DUN- BAR, doctor of medicine, acitizen of the German Empire, and a resident of Hamburg, Germany, haveinvented a certain new and useful Improved Method of Biological Purilication of Liquids, of which the following is a specification.

This invention relates to an improved method for the oxidation orbiological treatment of liquids for the purification of waste waters andparticularly sewage-waters.

According to the processes hitherto employed the crude sewage has in themajority of cases to be subjected to preparatory treatment more or lessinconvenient and costly before it is passed into a percolating-bed orcontact-bed, or both, as the oase may be.

Now the object of this invention is to provide an improved method ofcontinuous biological purification of sewage and other liq- -uids and animproved form of percolatingbed and mode of operation of same, wherebythe sewage may be efectually purified without preparatory treatment in asimple, continuous, and economical manner and without having recourse tomechanical methods of regulation and distribution. According to thisnovel method the unprepared sewage is passed directly into apercolating-bed and is effectively purified in a continuous manner bysubjecting it to the continuously-operative processes of absorption,biological action and oxidation in a plant suitably designed to bringthese operations forcibly and effectively into play.

The improved method excels in respect of successfully purifyingagivenvolume of crude sewage at a greater rate per unit of ground areaoccupied and usually at lower initial and working costs than in the caseof other existing methods.

The means employed for carrying the invention into practice consists,broadly, of an oxidation-body constructed, for example, of coke, slag,or other suitable material, the upper surface of this body beingprovided either wholly or in part with a layer of line granularmaterial, underneath which may be arranged one or more layers ofsomewhat coaser granular formation. Below these is arranged anunderstructure composed of larger piecesu say of a size of about sixinches in diameter and upward. vThe whole bed may be sunk below or builtfrom the ground-level, and a channel is provided running longitudinallyof the bed and provided with perforated coverings for the drainage ofthe effluent and the supply of air to the bed. The ground on either sideof the channel is sloped to drain toward same. The channel may terminatein an inspection-chamber connected to a drain or ditch for the disposalofthe effluent. The line upper layers of the bed are arranged withupwardly-extending sides to prevent the overflow of liquid to theunderstructure without passing through the fine layers. The liquid maybe passed on to the top layer from a receiving chamber or tank, whichmay also serve the purpose of screening the liquid from floatingdetritus.

A most important feature in the relative arrange-ment of the fine andcoarse layers according to this invention is the fact that a portion orportions of the coarse understructure are exposed to the atmosphere,thereby affording a free passage for air-currents and also an outlet tothe current of air which enters the bed from the bottom channel and ismaintained by the diiference of temperature within and without the bed,owing to the heat generated by the actions occurring in the bed.

A further feature is that the finely-granular constitution of the upperlayer serves to distribute the liquid to be purified in a finelydividedstate, such as in the form of films or drops, uniformly over the surfaceof the oxidation body and also furnishes a certain resistance whichprevents more of the liquid to be treated from passing through the bedthan the latter is capable of purifying or oxidizing without overtaxingits capacity. At the same time processes of absorption and decompositiontake place in it, which result in relieving theunderstructure.Further,undissolvedma terials are retained upon the surface or in thelayer of fine material and prevented from reaching the understructure.

The function of the intermediate layer or layers is to-prevent thewashing away of the material of the finer top layer into theunderstructure. In addition to this the uniform distribution of theliquid which has been begun in the top layer is further developed inthis transition layer.

The beds may conveniently be constructed of a length of fifty meters ormore and from eight to ten meters or more wide. The liquid to bepurified may be supplied through channels provided at intervals withlateral outlets. Under each of these outlets bricks, plates, or othersuitable devices may be laid IOO upon the top layer in order to preventthe washing away of this layer by the stream of liquid and to distributethis latter in the form of sheets.

In order that my invention may be readily understood and carried intoeffect, I will now proceed to describe the same fully, with reference tothe accompanying drawings, in Which- Figure 1 represents in ground plan,and

Figs. 2 and 3 in sectional elevations on lines fr and y y, respectively,the improved plant. Fig. 4 shows a sectional elevation of a modifiedarrangement of the bed. Fig. 5 is, on a somewhat larger scale, a groundplan showing a number of such beds in conjunction and a modified form ofcertain parts. Fig. 6 is a sectional elevation on the line .e z, Fig. 5.Fig. 7 is a sectional elevation illustrating a further-modifiedarrangement of the bed; and Fig. 8 is a sectional elevation of the bed,showing a modified form of the upwardly-extending sides for the toplayer.

Similar letters of reference refer to similar parts throughout thefigures.

Referring to the drawings, a is the fine upper layer withupwardly-extending sides a.

b is the transition layer, and c the understructure of larger-sizedmaterial, the portions of the understructure exposed to atmosphere andallowing a free air-passage being marked c.

Z is the channel for air-inlet and efiiuent drainage with perforatedcovers e.

f is the inspection-chamber with drain g.

i is the reception-chamber for the liquid, which enters by pipe la andis screened at il, passing out through pipe j into a suitabledistributing-trough or overfall-channel Z, having distributing branchchannels Z, whence it fiows onto the bed a and is evenly distributedthrough the bed, passing out through channel l in a purified condition.

In Fig. 4: is shown a modified arrangement of the bed -in which thewhole body is sunk into the ground. In this case the exposed portionofthe body c is shown at c and is disposed horizontally. I may use anynumber of such beds in conjunction, as indicated, for instance, in Figs.5 and 6. The liquid to be purified is supplied through a conduit-pipe 7Land pipes or nozzles j, leadingv into the distributing-channels l, whichlatter are provided with holes or outlets Z2. Under each of theseoutlets bricks m (plates or other suitable devices) arel laid upon orpartly in the top layer a in order to prevent the washing away of thislayer by the stream of liquid and to distribute this latter in the formof sheets. The exposed interspaces c2 of the understructure c `may bearranged as shown.

In the modification shown in Fig. 7 the exneed not necessarily becomposed of the same' layers of such mud may be placed one upon theother. Owing to the fact that in removing each layer of mud a portion ofthe finelygranulated top layer remains adhering thereto and is so left,between the separate layers of the piled-up solidified masses of mudfinelygranulated substances areohtained which produce a draining effectand permit of the further drying of the mud by evaporation and thesupply of air requisite therefor. The waste or loss in the top layer ofeach bed is replaced as required.

In accordance with the manner in which the liquid is to be treated, ortheconcentration of the liquids to be purified, or the conditions laiddown as to the degree of purity of the efiluenu the size of the granulesand also the thickness of the top layer will be arrived at for eachcase. According as the top layerl is higher and its granules finer thegreater will be the degree of purity obtained; but, of course, thequantitative efficiency will fall correspondingly. Consequently bysuitably dimensioning the top layer the plant may be suited to varyingquantitative and qualitative requirements.

The efficiency of the operation as conducted by the passage of theliquid through the novel apparatus or plant is based upon the fact thatthe liquid in its suitable quantitative regulation and distributionthroughout the bed is vigorously exposed to absorption, oxidation, andbiological infiuences.

By absorption is here meant the physical property peculiar to suchsubstances as those of which the b ed is composed of giving rise incertain organic compounds and gases in contact therewith to a state ofabnormal molecular activity, resulting in some cases in a change ofmolecular state and resolution into other and simpler compounds.Similarly as regards the well -known oxidizing eliiciency of coke andlike bodies this may be said y to be due to a like physical action owingto the peculiar surface formation of the bodies, which induces in theatmospheric oxygen a state of. molecular instability and accompanied bygreat readiness to enter into combination with substances which inpassing through the bed are exposed to this oxidizing influence.

It should be noted that the continuous maintenance of the action ofabsorption, as also of biological activity, is dependent upon thecontinuous supply of air to all parts of the bed. It is owing' to thedue appreciation of the liquid portions between the large pieces of thelowermostlayer, the sides of the layers of filtering materials of thebed being directly exposed to the atmosphereand causing a naturalcirculation of air from the sides of the bed to the interior and outagain by the heat set up by the oxidation in the bed, whereby the liquiddropping between the coarse pieces is surrounded by air and the use ofconduits and forcing apparatus is avoided.

' WILLIAM PHILIPPS DUNBAR. Witnesses:

MAX KAEMPFF, E. H. L. MUMMENHOFF.

